the reduction of a patient's body temperature to counteract prolonged high fever caused by an infectious or neurological disease or, less frequently, as an adjunct to anesthesia in heart or brain surgery.
method Hypothermia may be produced by placing crushed ice around the patient, by immersing the body in ice water, by autotransfusing blood after it is circulated through coils submerged in a refrigerant, or most commonly by applying cooling blankets or vinyl pads containing coils through which cold water and alcohol are circulated by a pump. The cooling unit is placed in an open area. Any kinks or twists in the tubing are removed, and the blanket is checked for leaks. The patient is wrapped in bath blankets, and then covered with the cooling blanket. The patient's temperature, registered by means of a probe inserted into the rectum, is read and recorded before hypothermia is initiated, every 5 minutes until the desired reduction is achieved, and then every 15 minutes. The blood pressure, pulse, respirations, and neurological status are checked every 5 to 10 minutes until the temperature is stabilized, then every 30 minutes for 2 hours, every 4 hours for the next 24 hours, and subsequently as required. Every 1 to 2 hours the patient is assisted in turning, coughing, and deep breathing. At similar intervals the chest is auscultated for breath sounds, and oral, nose, and skin care are administered; the skin is lubricated with oil or lotion before and during the procedure. An indwelling catheter is connected to a closed gravity drainage system, as ordered, and fluid intake and output are measured; if less than 30 mL of urine per hour is excreted, the physician is notified. If the patient's oral temperature is less than 90° F (32.2° C), the gag reflex is tested before any oral fluids or foods are administered. Nasooral suction is performed as indicated, body alignment is maintained, and passive or active range-of-motion exercises are performed every 4 hours. Because shivering increases body heat, medication for its prevention, such as chlorpromazine hydrochloride, may be ordered. The patient is observed for medication reactions, decrease in blood pressure, bradycardia, arrhythmias, bradypnea, respiratory failure, unequal pupils, increase in intracranial pressure, changes in consciousness, intestinal ileus, and frostbite. Any changes in skin color or signs of edema and induration are reported to the physician immediately. At the termination of therapy, the cooling blanket is replaced by regular blankets, and the patient usually warms at his or her own rate. As the patient's temperature approaches normal, the warming blankets are removed, but the temperature probe remains in place until the body temperature is stable.
interventions The technician administers hypothermia, carefully monitoring the patient's vital signs and any evidence of complications.
outcome criteria Hypothermia therapy used in the treatment of high fever associated with generalized severe infections reduces body heat by decreasing metabolism and inhibits the multiplication of the causative pathogenic organisms. Patients with a high temperature caused by a neurological disease may be maintained in a state of mild hypothermia (87° F to 95° F or 30.6° C to 35° C) for as long as 5 days. The procedure is successful if the fever is broken and complications do not occur.
hy·po·ther·mi·a ther·a·py(hīpō-thĕrmē-ă thāră-pē)
Cooling the patient's body below normal body temperature to prevent cerebral damage after cardiac arrest or trauma.